Honestly, when I'm doing most roller motors I don't even bother with a dedicated break in oil...... But I wouldn't argue against it.
For the past several years I've been using Brad Penn 15w-40 for the roller motor testing.
For my roller engines I dont add anything special
and there is no break in.. set the timing and carb
and go beat on it.. then change the oil and filter
after the week end
I noticed the companies pushing (is that too strong of a word?) their break-in oils talk about how it's supposed to improve ring seal, in addition to being a benefit to flat-tappet cam break-ins. It would be nice to know if engines run initially on this break-in stuff do actually seal up better or not.
Also, as at least on other person mentioned a) it's entirely possible to have too much zinc, and b) high-detergent oils do counteract the effects of the anti-wear additives by "scrubbing" the surfaces of the anti-wear components.
Some of the break-in oils have, IMO, too freakin' much zinc in them... strikes me that those companies' Marketing Departments had more say about the composition of their break-in oils than the Engineering Departments did.
